Countermeasures
Weapons are frequently a few steps ahead of countermeasures, and mines are no exception. In this field the British, with their large seagoing navy, have had the bulk of world experience, and most anti-mine developments, such as de-gaussing and the double-L sweep were British inventions. When on operational missions, such as the recent invasion of Iraq, the US still rely on British and Canadian minesweeping services. The US has worked on some innovative mine hunting countermeasures, such as the use of military dolphins to detect and flag mines. However, they are of questionable effectiveness.
Read more about this topic: Naval Mine